Field of the Invention
When we speak of alternative energy, we are often talking about huge wind turbines; a conventional alternative energy. The present invention relates to an alternative to conventional fossil fuel and nuclear as well as an alternative to what is viewed as one of the conventional alternative means of producing power—a typical wind turbine. The invention will produce fresh water and electricity from the combination of ambient wind and the temperature difference between ambient air and deep ocean water.
One of the largest storehouses of energy lies quietly at the bottom of the ocean. It is not oil, and it is not methane hydrate. It is cold water. Specifically, it is deep ocean water from the upper levels of the Midnight Zone at 3,300 to 13,200 feet deep (1000 to 4000 meters). Approximately 90% of the ocean by volume is deep ocean water. This water is at a temperature of 32° to 37° F. (0° to 3° C.). More correctly, it might be called a storehouse of a relative lack of energy because it is only the combination with a more energetic (warmer) mass that results in an extractable form of energy. That more energetic mass would, of course, be the warm upper regions of the Twilight Zone and the Sunlight Zone of the ocean and the tropospheric layer of the atmosphere.
Although this is the coldest water, anything 2,500 feet (762 meters) and deeper in the ocean is about 46° F. (8° C.), which is usable for applications involving the herein described invention. More than 90% of the oceans are greater than 2,500 feet (762 meters). I will hereafter refer to this as cold ocean water to differentiate it from the established term deep ocean water, or DOW.
The best place to exploit this temperature differential is the Tropics where the temperatures near and above the surface of the water are mild to hot year around. Fortunately, approximately 40% of the world's surface lies in the Tropics and it includes a lot of DOW and cold ocean water. While a tropical climate is the most efficient location for extracting water and power, an appreciable percentage of the North and South temperate zones have sufficiently warm weather to make this practical. For the United States that would include the coastline and offshore of states along the Gulf of Mexico, the eastern coast of Florida and the southern coast of California.
Fossil fuel has dual liabilities. First, it is a finite resource with increasingly high production costs and, secondly, contributes to a rising build-up of CO2 in the atmosphere. Nuclear has another set of problems involving long-term waste storage and hard-to-calculate catastrophe risks. At our current level of civilization, deep ocean water represents a relatively infinite supply of energy that can be exploited without adding greenhouse gasses or waste heat or radiation to the atmosphere.
Notwithstanding all the talk of peak oil, an even more pressing issue for the future growth of mankind is water. Peak water may have already occurred. The major constriction for increasing food supply for a burgeoning population is water, not land. According to the International Food Policy Research Institute, nearly 5 billion people, about half of global grain production, and 45% of the GPD ($63 trillion dollars) will be at risk due to lack of water with current consumption practices. Eighteen countries are now over-pumping their aquifers. This includes the big-three grain producers—China, India and the U.S.—and several populous countries such as Iran, Pakistan and Mexico. For 20 years Saudi Arabia was self-sufficient in growing wheat. They have nearly exhausted their aquifers and will quit growing wheat in the year 2016. Water shortages in California and Brazil are affecting the lives of millions of people and could affect food prices worldwide if drought conditions continue through 2015 and beyond.
We have energy alternatives to oil, but there are, as yet, no viable equivalent alternatives for water. As a byproduct of producing electricity, deep ocean water and cold ocean water can be used to supply a large amount of fresh water to a world more and more in need of it.
Description of the Related Art
The following is a tabulation of some prior art that presently appears relevant.
U.S. PatentsKindPat. No.CodeIssue DatePatentee7,748,946B2Jul. 6, 2010Rongbo Wan8,117,843B2Feb. 21, 2012Robert JamesHoward, et al20140138236A1May 22, 2014Keith White8,277,614B2Oct. 2, 2012Majed MohalAlhazmy
Conventional wind turbines are large; 130 to 300 feet (40 to 91 meters) in diameter. They are a prominent arrangement of blades, generator and gearbox sitting atop a relatively thin tower. A 2-megawatt Gamesa G87 weighs 334 tons US (303 tons metric). The nacelle alone weighs 72 tons US (65 tons metric). The blades are 42 tons US (38 metric tons) and the tower is 220 tons US (200 tons metric). The base adds another 1000 tons US (907 tons metric) of steel and concrete. It needs a footprint of over 100 acres (405,000 square meters). Transportation of the parts require extensive infrastructure. Roads have to be strong, wide and straight. The power they generate fluctuates with the wind and adds to the complexity of keeping a steady amount of power fed to the electrical grid. Base power plants running on fossil fuels are reduced in efficiency when required to ramp up and down with the vagaries of the wind. They can be seen for miles in all directions. The sound that wind turbines produces has been linked to migraine-like symptoms in humans living nearby as well as panic attacks, insomnia, tachycardia, and tinnitus. The flickering shadow the blades cast during the day has now been tied to depression. They kill an estimated 900,000 bats and 600,000 birds a year (2012) in the U.S. alone. There are many patents concerning wind turbines, with quite a few in public domain. Much of the current intellectual property concerning wind turbines deals with problems surrounding their operation. An example of this is U.S. Pat. No. 7,748,946 (2010), Rongbo Wan, dealing with the overheating of rotating parts in the nacelle.
Ocean thermal energy conversion, OTEC, uses closed or open type systems and low-pressure turbines to exploit the temperature gradient. Basically, the temperature differential is used to alternately vaporize fluids, run the vapor through a turbine and condense the vapor back into a liquid. These fluids have to have a low temperature of vaporization. These are complex mechanical systems with many components that add to the possibility of leakage of working fluids such as ammonia or refrigerant fluids into the environment. One such patent is U.S. Pat. No. 8,117,843 (2012), Robert James Howard et al, which involves the establishment of a cold thermal mass at deep ocean water depths and raising it up to be coupled to a warm water mass at the surface. This mass could be clathrates or ammonia, either of which could harm the environment if allowed to leak into the atmosphere.
An atmospheric water generator, AWG, extracts water from humid ambient air. Typically compressors and fans are used, making the extraction of water from the air a process that can be energy intensive. U.S. patent 20140138236 (2014), Keith White, describes an atmospheric water generator that could also produce electricity while harvesting water from a heat exchanger coil, but it involves environmentally challenging refrigerants and uses conventional means to cool the refrigerant back down. That would mean either a source of cold water or a conventional refrigeration unit.
Desalination plants typically use 15,000 kilowatt hours per one million gallons of fresh water produced. The water ends up costing about $2.5-4 dollars per 1,000 gallons (3800 L) depending on the price of electricity. U.S. Pat. No. 8,277,614 (2012), Majed Moalla Alhazmy, describes a plant that uses multiple flash chambers and counter-flow of heating and cooling mediums to increase the efficiency; however, the energy required to heat water to the point that it or a portion of it will become vapor requires some externally applied heat. Energy is also needed for pumps to move the heated and cooling liquid through flash chambers and heat exchangers.